Nuclear magnetic resonance is being applied to the study of transfer RNA, and of related proteins. Current emphasis is on identification, structure, and dynamic behavior of tRNA. Identification and structure are being approached mainly by nuclear Overhauser effect, as well as studies of carefully chosen different tRNA species. Dynamic behavior is being inferred mainly from studies of solvent exchange rates, measured by line broadening, by relaxation-time measurement, and by rapid change of solvent from H2O to D2O.